It is known with the help of a torch or plasma burner having a cutting burner device thereon, to cut a work piece having any desired outline, from a metal plate in which the burner is guided by hand or with the help of appropriate control devices (photoelectric scanning devices or numerical controls, etc.) over the metal plate and, in accordance with the outline of the work piece. The guiding mechanism generally used in such cases is a dual-axle machine which permits the cutting torch or burner to be moved in the x or y directions of this coordinate system.
Such dual-axle machines became known (for example from German laid open application (Auselegeschrift) DOS No. 2,207,873, especially FIG. 1 thereof), in which several cutting torches or burners are mechanically coupled with each other and all cutting torches are operatively moved by a signal of a control device in a uniform fashion. As a result it is possible to cut out simultaneously several similarly shaped work pieces, but each of the work pieces is cut out by a single torch.
In addition to the dual-axle machines there are the so called three-axle machines also known (such as from British Patent No. 917,376). In the last mentioned machines, a pair of cutting torches or burners are provided with a control arrangement so that is becomes possible that both cutting torches can be moved with the same speed in one coordinate direction (y-direction), while they can be moved with different speeds in the other coordinate direction (-x, +x). As a result, one may attain that simultaneously two different work piece outlines can be cut.
Notwithstanding the above-discussed state of the prior art known to applicants, on work pieces which have a similar outline on both sides of an axis of symmetry, that is, which both sides are mirror images of each other, so far exclusively only dual-axle machines have been in use for the cutting. One reason for this was that the dual-axle machines due to their simple controls are substantially less expensive than the three-axle machines.
With such dual-axle machines when a plurality of torches or burners are used to cut the work piece, a substantial increase in the productivity and thereby the economical use of the entire cutting machine could be attained since there is a constant pressure on the user of such machines to increase both of such factors.
An additional factor should also be considered, namely that when work pieces are cut out with torches, they must be free from buckling or warping due to heat in order to save time and costs in their subsequent processing period. Such heat warping usually is especially noticeable and takes place when the length of the work piece is substantially larger than the width of the work piece.